chore: Update project metadata (#83)

This commit updates the various links in the project metadata following the migration to the `istanbuljs` organization on Github.

README.md

@@ -13,7 +13,7 @@ loaded via child processes rather than via `require()`.
 It can also be handy if you want to run your own mock executable
 instead of some other thing when child procs call into it.
 
-[![Build Status](https://travis-ci.org/tapjs/spawn-wrap.svg)](https://travis-ci.org/tapjs/spawn-wrap) [![Build status](https://ci.appveyor.com/api/projects/status/oea7gdvqa0qeijrm?svg=true)](https://ci.appveyor.com/project/isaacs/spawn-wrap)
+[![Build Status](https://travis-ci.org/istanbuljs/spawn-wrap.svg)](https://travis-ci.org/istanbuljs/spawn-wrap)
 
 ## USAGE
 

package.json

@@ -23,14 +23,14 @@
   },
   "repository": {
     "type": "git",
-    "url": "git+https://github.com/isaacs/spawn-wrap.git"
+    "url": "git+https://github.com/istanbuljs/spawn-wrap.git"
   },
   "author": "Isaac Z. Schlueter <[email protected]> (http://blog.izs.me/)",
   "license": "ISC",
   "bugs": {
-    "url": "https://github.com/isaacs/spawn-wrap/issues"
+    "url": "https://github.com/istanbuljs/spawn-wrap/issues"
   },
-  "homepage": "https://github.com/isaacs/spawn-wrap#readme",
+  "homepage": "https://github.com/istanbuljs/spawn-wrap#readme",
   "devDependencies": {
     "tap": "^13.0.0-rc.25"
   },